Relay with a balanced operating member actuated by an energizable armature



FIGB May 30, 1967 T. R. WELCH 3,323,085

RELAY WITH A BALANCED OPERATING MEMBER ACTUATED BY AN ENERGIZABLE ARMATURE Filed Aug. 16, 1965 2 Sheets-Sheet 1 FIG1 FIG 2 PRIOR ART PRIOR ART INVENTOR. T OMAS Pass WELCH A F R Y Y5 May 30, 1967 T. R. WELCH 3,323,085

RELAY WITH A BALANCED OPERATING MEMBER ACTUATED BY AN ENERGIZABLE ARMATURE Filed Aug. 16,. 1965 2 Sheets-Sheet 2 v FIG5 m g Liil-iiil INVENTOR. THOMAS Ross WELCh' BY Arz'oz/vzvs United States Patent RELAY WITH A BALhNED OPERATING MEM- BER ACTUATED BY AN ENERGIZABLE ARMA- rum:

This invention relates to relays and more particularly to improvements in multicontact relay construction.

The demand on the relay industry has been for con tinual improvement of reliability, with smaller and smaller overall relay size. The reduction in size affects the coil size; therefore, the amount of magnetomotive force capaable of being developed by the coil is reduced. This usually results in a reduction of contact pressures and contact gaps Which decrease the relays reliability.

To compensate for the resulting reduction in contact pressure, elaborate contact materials, including contact plating and cleaning systems have been developed. All of these compensations, even though each is good in its own way, are poor substitutes for low contact pressure.

In addition to the demand to provide small relays, the demand has been to produce relays which operate reliably with a minimum of power. Such relays are particularly desirable for various military applications, where a great many relays are employed, but where the total amount of available power maybe limited.

Accordingly, it is an object of the invention to provide a novel relay which requires less power to operate as compared with prior art relays.

Another object of the invention is the provision of a multicontact relay which is reliably operable in either of two states with a minimum of energizing power.

A further object is to provide a relay which is relatively inexpensive and which operates more efficiently and reliably than prior art relays.

Still a further object is the provision of a relay which is capable of snap action from one operating state to another in response to a minimum of energizing power.

These and other objects of the invention are accomplished by providing a relay in which the various movable contacts or blades are biased to apply substantially balancing forces to a pivotable operating member of the relay, so that a minimum of power is required to drive the member from an off position to an on position. A conventional relay armature with a driving member coupled thereto are also included. When the armature is in a tie-energized state, the driving member is not in contact with the operating member, which is therefore free to assume the off position, in which the movable blades of the relay are at their normally closed contact positions. However, when the armature is energized, after gaining sufficient momentum, the driving member drives the operating member with a snap action to the on position, in which the movable blades are driven to their normally open contact positions. Thus, the balancing of the forces, reduces the power necessary to drive the operating member from the off to the on position, while the driving of the operating member by the driving member connected to the armature, provides the snap action, at which the operating member is driven to the on position.

The novel features that are considered characteristic of this invention are set forth with particularity in the appended claims. The invention itself both as to its organization and method of operation, as well as additional objects and advantages thereof, will best be understood from the following description when read in connection with the accompanying drawings, in which:

FIGURE 1 is a force function graph of the relay forces for a single pole, double throw relay;

Patented May 30, 1967 FIGURE 2 is a schematic type plan drawing of a single pole, double throw set of relay contacts, and the actuating mechanism;

FIGURE 3 is a force function graph of a double pole, double throw relay;

FIGURE 4 is a schematic type plan drawing of the contacts structure of a double pole, double throw relay;

FIGURE 5 is a force function graph of a relay with the modifications as per this invention;

FIGURE 6 is a schematic type plan drawing of a double pole, double throw, relay contact structure embodying the features of this invention and showing the method of adjusting the contacts;

FIGURE 7 is a schematic type plan drawing incorporating the operating member into the contacts of FIGURE 6 and also showing versions of this invention adapted to latching relays and non-latching relays; and

FIGURE 8 is a schematic type plan drawing of one version of the invention applied to non-latching type relays.

As a means of fully describing the present invention and showing the action and advantages thereof, there will be employed what have been called force function curves as illustrated in FIGURES 1, 3 and 5. This type of curve has now been used in the relay industry for sometime to illustrate the forces involved as the relay functions. Note, for example, the paper entitled, Accurate Prediction of Relay Performance and Reliability with Force Function Measurement-s before the Sixth National Conference on Electromagnetic Relays at the Oklahoma State University, Stillwater, Oklahoma on April 8, 9 and 10, 1958. i

This type of curve is presented in the standard four quadrant type of Cartesian coordinates, with quadrants 1 and 4 normally being used, as will be used in these figures. This is for the purpose of showing the positive and negative forces involved in the relay. The ordinates are the forces. Above the center are the positive forces and below, the negative forces. The abscissa is distance, and in the case of these illustrations for relays, this is the distance of armature travel. At ordinate line 9 (FIGURE 1) the armature is completely closed on the poles of the relay. To the right, the armature is at its extreme open condition.

FIGURE 1 is a force function curve of an ordinary non-latching single pole, double throw relay that will be first described in order to better described this invention. FIGURE 2 is a schematic type plan view of a single pole double throw relay, the force function curve thereof being represented in FIGURE 1.

In detail, referring to FIGURES 1 and 2, line 8 is the abscissa and is an indication of relay armature travel. Line 9 is the ordinate line of armature forces. At the intersection of line 16 with line 8, the first pickup of an armature actuator 14 is made with a contact blade 15. As the armature 1 continues to close, i.e. rotate counterclockwise about pivot point 19, the force builds up as illustrated by the slope of line 16. The actuator 14, integrally associated with armature 1 applies pressure on contact 15 to separate it from a normally closed (NC) contact 12. At the point where contact blade 15 separates from contact 12, the slope of the line 16 changes to the slope of line 17, since at this point, the force involved in moving the armature no longer is the sum of the contact pressure of contact 12 and the spring force of the blade 15 and that of a return spring 10', but instead is the sum of the forces applied by the blade 15 on actuator 14 and return spring 10.

Referring back to the line 16, the abscissa line 5 now is an exact measure of the distance that the contact has traveled from the time of the first touching of actuator 14 with contact blade 15 until the contacts 15 and 12 open.

Therefore, the distance represented by line 5 is the overtravel of the normally closed contact. The vertical line SP is the force involved in this travel. Exact measurements and calculations can be done from these measurements on a relay, providing, of course, that these graphs are linear and are accurate, which is normally the case under good engineering conditions.

The horizontal line 7 is the contact gap, as measured by armature movement, from the time the contact blade 15 separates from normally closed contact 12 until it contacts a normally open contact 13, at which time the forces start to build up, as indicated by the slope of line 18. The abscissa line 6 represents an overtravel on the normally Open contact in relation to the forces represented by ordinate line 6F.

This combination of lines 16, 17 and 18 thus illustrates the total travel of the relay armature, and the buildup of the forces during this travel and the operation of the contacts.

The magnetic operating force necessary to operate this relay is shown in quadrant 4 of FIGURE 1 as line 2. Since it is easier to visualize the difference of these forces when they overlap, the complete line 2 has been shown dotted as line 102 in quadrant 1. Line 102 will be seen slightly above the lines 16, 17 and 18 and therefore representing a large amount of force or power necessary to provide the minimum forces for proper relay operation. Generally, the magnetic forces developed by the armature must exceed the contact and other resisting forces of the relay.

FIGURE 3 shows a force function diagram of a double pole, double throw relay as shown in FIGURE 4, the additional set of contacts being designated by primed numerals. FIGURE 3 is similar to FIGURE 1 except that since two sets of contacts are now being operated in the conventional manner, the forces involved are higher than the forces explained for FIGURE 1. For instance, as actuator 14 contacts'blade 15 and actuator 14' contacts blade 15, the slope of the line 26 is now twice as high as previously shown for line 16, even though the overtravel line 5 is not greater than line 5. The force 5'F is approximately twice as great as force 5F, providing that both contact blade forces 15 and 15 are equal.

In FIGURE 3, lines 27 and 28 correspond to lines 17 and. 18 of FIGURE 1. From FIGURE 3, it thus becomes apparent that whereas the power represented by line 102 is sufiicient to operate a single pole double throw relay, it is insufiicient for a double pole relay. A much larger force, represented by a line 103, is required to overcome the'internal relay forces. The present invention provides a novel relay which minimizes the forces required for its proper operation.

The advantages of the present invention can be illustrated by the force function diagram of FIGURE 5 for the double pole, double throw contacts diagrammed in FIGURE 6. For the sake of comparison, lines 16, 17 and 18 of FIGURE 1 are again shown in FIGURE 5 with line 102, which is necessary to operate these spring forces for a single pole, double throw relay. Line 103 is also shown, which represents the force required to operate a double pole, double throw relay. With reference to FIG- UREV6, blade 15 is again pressed against normally closed contact 12, but unlike the conventional relay, the direction of force or bias of the other blade, shown as 15", is reversed. Instead of biasing it to be in contact with normally closed contact 12', it is pressured or biased towards normally open contact 13'.

In order to return the contact 13 to the condition of being normally open and contact 12 to being normally closed, and to further accomplish this invention, there is inserted an operating means or member 50 which pivots 0n the same pivot 19 as the armature. This operating memberhas an actuator 14, the same as the conventional relay had, but in place of the previous actuator 14 of FIGURE 4, an actuator 51 is used.

It should be noted that actuator 51 contacts the blade 15" on the opposite side of blade 15" as is conventionally done, as was previously done by actuator 14' in contacting blade 15' (see FIGURE 4). The result is that contact blade 15" is pressed against contact 12, as shown in FIGURE 7, which returns 12. to the condition of being normally closed and 13 being normally open, so that there has been no change in the electrical circuitry, or the positions of what the industry terms the normally closed and normally open contact. A definite change how ever has occurred in the relationship of the forces of the relay, for now blade 15" is continually pressing against the actuator 51 and tending to move it in the counterclockwise direction. This will be termed a negative force and direction.

Referring now to the force diagram, FIGURE 5, in quadrant 1, the line 16 again represents the pressure of normally closed contact 12 against actuator 14. Line 36 in quadrant 4 represents the pressure of normally closed contact 12 against actuator 51. The pressures on 14 and 51 counteract each other through operating member 50. Since line 16 is in the positive direction and line 36 in the negative direction, as shown on the graph FIGURE 5, the resultant, if the contacts were in exact balance, would be Zero and therefore the force curve would go along the abscissa line 8. The preferred method however, is to either have a return spring, such as 10, in the relay operation, which would unbalance this counteraction slightly, or to keep an unbalance in the adjustment of the contacts 12, 12 so that there is a slight pressure, such as shown by resultant line 46. In the position shown in FIGURE 7, the operating member 50 is aided by the pressure of blade 15" on the actuator 51, so that a much smaller force is required to rotate the armature in a counterclockwise direction.

At the end of line 46, the line 47 continues, 'being the resultant of the counteraction of blades 15 and 15 and spring 10. Line 47 represents the net force of the forces represented by line 17 and negative line 37. After the blades have reached normally open contacts 13 and 13', the forces represented by lines 18 and 38 produce a resultant force as shown by line 48.

As demonstrated by lines 46, 47 and 48, the counteraction of forces results in much lower power required to operate the relay. It is not only lower than the original value for a double pole relay, as represented by the line 103, but even lower than that shown for the single pole relay, as represented by line 102. Actually the required power can be lowered to the value represented by line 104.

The contact arrangement shown in FIGURE 7 is almost ideal for a latching relay where the operating member 50 is the armature of the relay, with the modifications of actuators as described. In a magnetic latching relay, a magnetic pole replaces pole 97 and a permanent magnet is inserted between core 106 and the member 50, which now serves both as an operating member and an armature. This permanent magnet polarizes the member 50 through the air gap between 105 and member 50, which gap allows 50 to move. For the sake of illustration, consider the magnet 105 polarizing the member 50 as a North Pole. When the coil or coils 120, 121 on core 106 are energized in the proper direction, they will make pole 100 North and pole 98 South. This will make pole 100 repel the member 50 and pole 98 will attract it, with the result that a counterclockwise moment is applied, closing the member 50 on pole 98. This closes the blade 15 to contact 12 and blade 15" to contact 12.

In a latching relay, no return spring 10 is needed and it is not necessary to leave an unbalance of the counteracting spring forces, since the latching action of the relay, by the magnetic attraction of the poles of the relay, will hold the armature in either operating position. The armature as the operating member will transfer from one latching position to the other with great ease, because of the small net forces required in the novel relay of the present invention.

It should be stated that the criteria for relay failure under shock and vibration conditions are very critical. Military specifications class any opening of the contacts in exces of 100 microseconds as a failure. In many specifications, this criterion of failure is even down as small as microseconds. Thus the slightest motion of the armature against the contacts is enough to open them for this momentary period. In the latching relay, as previously stated, the operating member armature 50 is held by the latching force 82 or 83 (FIGURE 5) which is great enough to keep the relatively heavy armature from moving under vibration or shock. In a non-latching relay, however, this is not the case. In fact, the very advantage of the low operating forces may seem as a disadvantage. This is overcome by this invention as follows.

To the non-latching relay is added an operating member that operates like the previous member 50, but in this case is not the armature.

This arrangement is shown schematically in FIGURE 8. The relay is shown in the deenergized position, with the armature 53 against the stop 54. Spring 10' drives operating member 61 to an off or de-energized position. When the coil 55 is energized, poles 56 and 57 attract armature 53, which pivots on bearing 60, and compresses spring 59 as the armature leaves stop 54. The armature leaving the stop 54 is line 64 in FIGURE 5. A drive 62 is attached to the armature 53 and as the armature pivots, the driver 62 approaches pivoted operating member '61. The compression of return spring 59 is shown by line 63 in FIGURE 5. When the driver 62 contacts the operating member 61, it causes the member 61 to pivot about its bearing 60. This part of the operation is shown by the intersection of lines 63 and 46 in FIGURE 5. As the armature continues to pivot, the previously described counteracting forces cause the operation to follow the remainder of line 46 and then lines 47 and 48 of FIGURE 5 as previously described.

When the coil 55 is deenergized, the unbalance of the counteracting forces plus return spring 59 returns the operating member 61 and the armature 53 to the point where 61 stops because the unbalance force is finally brought to complete equilibrium by and 15".bearing sufficiently against contact 12 and 12'. The driver 62 leaves operating member 61 at this point and continues to be returned to the stop 54' by the spring 59. In this deenergized condition, the space between driver 62 and operating member 61 serves by aiding the resistance to shock and vibration as well as giving the relay a snap action operation characteristic. The operating member 61 should preferably be nonmagnetic and of low mass, to minimize the effects of shock and vibration thereon, as well as minimize the force needed to move it from one position to another.

This space aids shock and vibration by allowing the armature to be able to move slight amounts without actuating the contacts. This space allows the spring 59 to absorb most of the energy before 62 can contact 61. Some of the other factors are the vibration frequency or the shock wave shape, the armature mass, the return spring pressure and the distance between 61 and 62, and of course the gravity (g) level of the shock or vibration.

For snap action, the stop 54 is adjusted until the intersection of lines 64 and 63 in FIGURE 5 intersect with the magnetic line 104. Line 104 is the same operate value or pull-in value as it is at other points on its curve. The armature is held against the stop 54 until the relay coil power is great enuogh to overcome the return spring values at intersection of 104, 63 and 64. By the time driver 62 contacts operating member 61, the armature has accelerated to a velocity that operating member 61 switches the contacts as previously described, but quite fast so that snap action results therefrom. It is appreciated by those familiar with the art that the location of this intersection point of lines 63, 64 and 104 cannot be expressed herein by any formula since it varies with every relay type in relation to the magnetic gap, magnetic pole area, magnetic pole shape, flux density, spring forces, return spring forces and even the relationship of binge in relation to magnetic pole area. Once this intersection point has been located for a given relay, future production can be controlled by controlling the slope of the return spring curve and setting the stop to exceed the critical minimum magnetic gap.

It is also the intention of this invention that in addition to the electromagnetic type of actuating means, other means, such as electrostr'ictive and magnistrictive actuating means, can be used to actuate the operating members as described.

From the foregoing, it should thus be appreciated by those familiar in the art that by providing a relay constructed in accordance with the teachings of the invention whereby the forces produced by the various contacts are counterbalanced by means of an operating member which operates on reversely biased blades, the power necesary to activate the relay is greatly reduced. In practice, very small relays, known as half-micro miniature relays, have been built in accordance with the teachings disclosed herein which required only 40 milliwatts of power. The contact gaps and pressures produced were equal to or greater than conventional relays requiring milliwatts and more. Also the vibration characteristics of the relays constructed in accordance with the teachings of the present invention were excellent, exceeding the military requirements for relays several times as powerful.

There has accordingly been shown and described herein a novel improved relay construction. It should be appreciated that those familiar with the art may make modifications in the arrangements as shown without departing from the spirit of the invention. For example, the teachings of the invention are not limited to multipole double throw relays. They are equally applicable in a single pole relay wherein the counterbalancing force is provided by a spring-like member rather than a member which acts as the movable contact or blade between contacts, such as blade 15 shown in FIGURE 4. Also, the teachings are applicable to single throw relays where the movable blades move towards a normally open (NO) contact or away from a normally closed (NC) contact. Therefore, all such modifications and equivalents are deemed to fall within the scope of the appended claims.

What is claimed is:

1. In a multicontact relay including at least two contact assemblies, each assembly comprising, a normally open contact, a normally closed contact and a blade, movable between the two contacts associated therewith, the improvement comprising:

a first movable blade having an end positioned between the normally open and normally closed contacts associated therewith and biased toward engagement with the normally closed contact associated therewith;

a second movable blade, having an end positioned between the normally open and normally closed contacts associated therewith and biased toward engagement with the normally open contact associated therewith;

a pivotably mounted operating member of electrically non-conductive and non-magnetic material, capable of assuming off and on positions;

a first spring coupled to said operating member to drive it to said off position, said operating member in the off position coupled to and driving said second blade to be in engagement with the normally closed contact associated therewith, while said first blade is free to be in contact with the normally closed contact associated therewith, against which it is biased, said second blade applying a first force to said operating member in a direction to pivot it to said on position, said first force alone being insufiicient to change the position of said operating member from said off position, said operating member in the on position being in contact with the first blade driving it to engage the normally open contact associated therewith, and said second blade is free to engage the normally open contact associated therewith, against which it is normally biased;

a pivotably mounted armature capable of assuming off and on positions;

a second spring connected to said armature, and stop means for controlling the off position of said armature;

a driving member integrally coupled to said armature spaced apart from said operating member when said armature is in said off position; and

means for energizing said armature to assume said on position in which said driving member engages said operating member driving it to its on position.

2. The multicontact relay defined in claim 1 wherein said driving member drives said operating member to its on position after said armature has a selected momentum when energized to assume its on position.

3. A relay comprising:

relay contacts including terminals for external connections to circuits,

some of the said contacts being biased to the normally closed contact positions thereof and others of said contacts being biased to the normally open contact positions thereof;

an operating member having on and off states, in contact in said 01f state with contacts biased to their 8 a normally open contact positions to drive them to their normally closed contact positions, while said operating member in said on state is in contact with contacts biased to their normally closed positions to drive them to their normally open contact positions;

spring means for driving said operating member to its off state;

an energizable armature and a driver coupled thereto having on and off states and positioned adjacent said operating member for switching said operating member to the on state when said armature is energized and for enabling said operating member to return to the off state when said armature is de-energized; and

means, electrically terminated for external connection,

for energizing said armature.

4. A relay as defined in claim 3 further comprising:

an armature return spring for returning said armature to the oiT state when said armature is de-energized.

References Cited UNITED STATES PATENTS 2,955,174 10/1960 Richert 20093 3,060,292 10/ 1962 Moenke 200-104 3,109,077 10/1963 Herman 200104 X BERNARD A. GILHEANY, Primary Examiner.

R. N. ENVALL, JR., Assistant Examiner. 

1. IN A MULTICONTACT RELAY INCLUDING AT LEAST TWO CONTACT ASSEMBLIES, EACH ASSEMBLY COMPRISING, A NORMALLY OPEN CONTACT, A NORMALLY CLOSED CONTACT AND A BLADE, MOVABEL BETWEEN THE TWO CONTACTS ASSOCIATED THEREWITH, THE IMPROVEMENT COMPRISING: A FIRST MOVABLE BLADE HAVING AN END POSITIONED BETWEEN THE NORMALLY OPEN AND NORMALLY CLOSED CONTACTS ASSOCIATED THEREWITH AND BIASED TOWARD ENGAGEMENT WITH THE NORMALLY CLOSED CONTACT ASSOCIATED THEREWITH; A SECOND MOVABLE BLADE, HAVING AN END POSITIONED BETWEEN THE NORMALLY OPEN AND NORMALLY CLOSED CONTACTS ASSOCIATED THEREWITH AND BIASED TOWARD ENGAGEMENT WITH THE NORMALLY OPEN CONTACT ASSOCIATED THERWITH; A PIVOTABLY MOUNTED OPERATING MEMBER OF ELECTRICALLY NON-CONDUCTIVE AND NON-MAGNETIC MATERIAL, CAPABLE OF ASSUMING OFF AND ON POSITIONS; A FIRST SPRING COUPLED TO SAID OPERATING MEMBER TO DRIVE IT OT SAID OFF POSITION, SAID OPERATING MEMBER IN THE OFF POSITION COUPLED TO AND DRIVING SAID SECOND CONTACT TO BE IN ENGAGEMENT WITH THE NORMALLY CLOSED CONTACT ASSOCIATED THEREWITH, WHILE SAID FIRST BLADE IS FREE TO BE IN CONTACT WITH THE NORMALLY CLOSED CONTACT ASSOCIATED THEREWITH, AGAINST WHICH IT IS BIASED, SAID SECOND BLADE APPLYING A FIRST FORCE TO SAID OPERATING MEMBER IN A DIRECTION TO PIVOT IT TO SAID ON POSITION, SAID FIRST FORCE ALONE BEING INSUFFICIENT TO CHANGE THE POSITION OF SAID OPERATING MEMBER FROM SAID OFF POSITION, SAID OPERATING MEMBER IN THE ON POSITION 